Over the past four decades, researchers have used different theoretical and methodological approaches to study social inequalities in health, so the aim of this study is to analyze the main approaches to studying social and socio-economic inequalities in health: materialist (based on income), psychosocial (based on social inequalities), cultural and behavioral (based on health / lifestyle behaviors) and intersectional (used to identify social inequalities in health among many social groups appear at the intersection between different identities of the individual). There are also the fundamental cause theory, in which SES and social class are defined as the "fundamental cause" of health, disease, disability and death, and the life-course theory covering all the models that explain health inequalities within research of social inequalities in health.
Social inequalities in health are understood as differences in health between social groups based on such social determinants as gender, age, income, level of education, occupation, employment / unemployment, marital status, presence of children in the family, living conditions, place of residence, etc., which are reproducing over the time. Social inequalities in health are unjust, so in civilized societies governments tackling social inequalities in health. Health equity means that everyone should be able to reach their full potential in health. Health equity is not the same as health equality, because those who have greater needs but fewer resources need more support to equalize opportunities.
Empirical studies, including those conducted in Ukraine, have shown the relationship between different social and economic determinants and health inequalities and have confirmed the existence of social inequalities in health among different socio-economic and demographic groups.